The Rubber Egg
MATERIALS:   a raw egg (with shell)
                           vinegar
                            small jar with lid
PROCEDURE:  1.  Fill the jar about half way
                                with the vinegar.
                           2.  Carefully place the egg
                                 in the jar and put the lid
                                 on the jar.
                            3.  Check the egg 24 hours
                                  later.
                                  What has happened??
EXPLANATION:  The acid in the vinegar
combined chemically with the calcium in the
egg shell.  As the calcium was removed, the
shell became soft and rubbery.
Now try this:
Instead of an egg, place some clean chicken
bones in a jar of vinegar, and observe the
bones after 48 hours.  Now tie the bones in
a knot, allow them to dry, and impress your
friends with bones that are tied in a knot!!